1
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0
Choose the correct statement.
A
Calcium and Magnesium metals are manufactured by electrolysis of aqueous solutions of their salts
B
The oxo-anion $\mathrm{ClO}_3^{-}$does not undergo disproportionation reaction
C
Nitride ion $\mathrm{N}^{-3}$ cannot act as an oxidising agent
D
In alkaline medium the reduction of $\mathrm{MnO}_4^{-}$ion involves gain of 5 electrons
2
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0
An aqueous solution of $\mathrm{CrCl}_3 .6 \mathrm{H}_2 \mathrm{O}$ (Molar mass $=266.5 \mathrm{~g} / \mathrm{mol}$ ) containing 2.665 g of the solute after processing, when treated with excess of $\mathrm{AgNO}_3$ gave 2.87 g of AgCl (Molar mass of $\mathrm{AgCl}=143.5 \mathrm{~g} / \mathrm{mol}$ ) Choose the correct formula of the compound which give these results.
A
$\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_4 \mathrm{Cl}_2\right] \mathrm{Cl} \cdot 2 \mathrm{H}_2 \mathrm{O}$
B
$\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_3 \mathrm{Cl}_3\right] \cdot 3 \mathrm{H}_2 \mathrm{O}$
C
$\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_5 \mathrm{Cl}\right] \mathrm{Cl}_2 \cdot \mathrm{H}_2 \mathrm{O}$
D
$\left[\mathrm{Cr}\left(\mathrm{H}_2 \mathrm{O}\right)_6\right] \mathrm{Cl}_3$
3
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0
In which one of the following pairs does the stability of the monovalent ion increase with respect to the molecule, while the magnetic character remains the same for both?
A
$\mathrm{C}_2 / \mathrm{C}_2^{+}$
B
$\mathrm{O}_2 / \mathrm{O}_2{ }^{+}$
C
$\mathrm{B}_2 / \mathrm{B}_2{ }^{+}$
D
$\mathrm{N}_2 / \mathrm{N}_2^{+}$
4
COMEDK 2025 Morning Shift
MCQ (Single Correct Answer)
+1
-0
When $9.2 \times 10^{-3} \mathrm{~kg}$ of formic acid is added to 600 ml of water the freezing point of water is depressed. If $30 \%$ of Formic acid undergoes dissociation what would be the freezing point of the solution? ( $\mathrm{K}_{\mathrm{f}}$ of $\mathrm{H}_2 \mathrm{O}$ is 1.86 K kg mol ; MM of formic acid: 46 amu )
A
273.9 K
B
272.2 K
C
270.1 K
D
270.8 K
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